Battery charging device

ABSTRACT

A battery charging device includes: a battery housing which delimits at least one battery receiving space at least in part; at least one power electronics unit supplying a charging voltage; and an electronics housing which (i) is formed separately from the battery housing, and (ii) accommodates the power electronics unit in at least one of water-protected manner and dust-protected manner.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a battery charging device in which abattery is inserted into a battery charging container in which a powerelectronics unit is situated.

2. Description of the Related Art

Battery charging devices have already been provided in which a batteryis inserted into a battery charging container in which a powerelectronics unit is situated.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to a battery charging device includinga battery housing which delimits at least in part at least a batteryreceiving space, and including at least one power electronics unit whichis at least designed to supply a charging voltage.

It is provided that the battery charging device include an electronicshousing which is formed separately from the battery housing, and whichis provided for accommodating the power electronics unit at leastwater-protected and/or dust-protected.

A “battery charging device” is to be understood to mean in particular adevice which is provided for charging an at least partly dischargedbattery and, for this purpose, to withdraw electrical energy in the formof current from a power line or a power source and transmit it to thebattery. In particular, the battery charging device includes at leastone current transformer unit which is designed to transform thewithdrawn energy into charging voltage. The term “provided” is to beunderstood to mean in particular specifically programmed, designed,and/or equipped. That an object is provided for a particular function isto be understood in particular to mean that the object fulfills and/orexecutes this particular function at least in one application stateand/or one operating state.

A “battery” is to be understood in particular to mean a rechargeableelectrical energy storage device, which stores electrical energy withina storage medium with the aid of a reversible, chemical reaction. Inprinciple, the battery may have multiple battery cells, which areconnected in series, the battery voltage being made up of a sum ofvoltages in the multiple battery cells. A “battery housing” is to beunderstood in particular to mean a housing which at least in partdelimits a battery receiving space. In particular, the battery housingmay delimit at least in part one other space in addition to the at leastone battery receiving space, a transformer element of the batteryhousing at least in part delimiting the at least one other space againstthe at least one battery receiving space.

“Delimiting at least in part” is to be understood to mean in particularthat a housing has at least openings through which elements are passedtoward a connection with an element, for example power supply elementsor heat dissipation elements, which is accommodated in the space whichis at least partially delimited by the housing, and/or through which anelement, which is to be accommodated in a space, which is at least inpart delimited by the housing, is introduced into the space which is atleast in part delimited by the housing. A “battery receiving space” isto be understood to mean in particular a space, which is provided toreceive a battery, the battery receiving space having at least onebattery interface, which is provided to transfer electrical energy tothe battery to be charged. In particular, a battery to be recharged ischarged when it is placed in the interface in a thus intended direction.“Receiving an element in a space” is to be understood to mean inparticular that, in a received state, the element is introduced into thespace to at least fifty percent of its entire volume.

A “power electronics unit” is to be understood to mean in particular aunit which includes the at least one current transformer unit andelectronic units for sensing a state of charge of the inserted batteryas well as for controlling a charging process. A “charging voltage” isto be understood to mean in particular a voltage which is used to chargethe battery. In particular, the charging voltage is identical with thebattery voltage with which the battery supplies current. An “electronicshousing” is to be understood to mean in particular a housing which atleast in part delimits an electronics receiving space. The electronicshousing is preferably designed as a cuboid housing. An “electronicsreceiving space” is to be understood to mean in particular a space, inwhich a power electronics unit is at least in part, preferablycompletely, accommodated. In particular, at least one power lineelement, which is provided to connect the at least one currenttransformer unit to a battery which is to be charged, is passed throughthe electronics housing. Preferably the at least one power line elementconnects the at least one current transformer unit and the batteryinterface.

“Water-protected and/or dust-protected” is to be understood to mean inparticular that the electronics housing prevents at least in oneoperating mode water and/or dust from penetrating into the electronicsreceiving space. In particular, the electronics housing fulfills safetyrequirements corresponding to a protection class according to theso-called IP Code according to DIN EN 60529 of IP34, advantageously atleast of IP35, preferably of at least IP55 and particularly preferablyof at least IP67. “An electronics housing which is formed separatelyfrom the battery housing” is to be understood to mean in particular anelectronics housing which has been formed separately from the batteryhousing and which is provided to be mounted on the battery housing in aform-fit and/or force-fit manner, the electronics receiving space whichis at least partly delimited by the electronics housing being at leastpartly separated from the battery receiving space by the electronicshousing after the electronics housing was mounted on the batteryhousing.

In particular, due to the design of the battery charging deviceaccording to the present invention, a safe and water-protected chargingof a battery may be achieved. The battery charging device according tothe present invention may in particular be used safely outside of anenclosed space even under unfavorable conditions, for example in rain.

In a refinement of the present invention it is provided that the atleast one electronics housing have at least one cover body and oneprincipal body. A “cover body” is to be understood to mean in particulara preferably plate-shaped body which delimits a space at least partly onat least one side. A “principal body” is to be understood to mean inparticular a body which at least partly delimits a space on at least twosides and preferably on all sides except for one side, which isdelimited at least in part by the cover body. In particular, a simplyconstructed electronics housing which may be manufactured at low costmay be achieved.

Furthermore it is provided that the at least one electronics housinghave at least one sealing unit which at least in part thermallydecouples the at least one cover body and the principal body. “At leastin part thermally decouples” is to be understood to mean in particularthat the at least one sealing unit has a heat transport volume powerdensity which is at most half the size, advantageously at most a fifththe size and preferably at most a tenth the size of the heat transportvolume power density of the cover body and the principal body of theelectronics housing so that thermal heat from the cover body or theprincipal body is only transferred to the principal body or the coverbody after a long delay. In particular, cooling may be focused on a partof the body of the electronics housing at which a largest amount of heataccrues. In particular, a temperature difference between the at leastone cover body and the principal body is at least in one operating mode,in which the battery charging device is operated at full capacity,approximately 10 degrees Celsius. The battery charging device is, inparticular, provided to transfer waste heat accruing in the powerelectronics either to the cover body or to the principal body so thatcooling may be better concentrated either on the cover body or on theprincipal body in order to prevent the power electronics fromoverheating. In particular, an easy heat management may be achieved.

Furthermore it is provided that the battery charging device include atleast one heat transporting element which thermally joins the at leastone cover body with the power electronics unit. A “heat transportingelement” is to be understood to mean in particular an element which isprovided to transport heat with the aid of thermal conductivity, thermalradiation or convection between two locations and which includes a heattransport capacity which is at least twice as high, advantageously atleast four times as high, and preferably at least ten times as high, asa heat transport capacity of elements which surround the heattransporting element. The heat transporting element is, in particular,designed as a heat transporting element which has a thermal conductivitywhich is at least twice as large, advantageously at least four times aslarge, and preferably at least ten times as large as a thermalconductivity of elements which surround the heat transporting element,in particular such as a heat conductivity of the principal body. Inparticular, the at least one heat transporting element may be made of ametal. Preferably the at least one heat transporting element may bedesigned as a metal cooling body, for example made of aluminum.Alternatively, for example, a heat pipe may be used. In particular, heatdissipation for the power electronics unit may be achieved with a highheat transport performance while, at the same time, high heating of thecomponents bordering the power electronics is avoided.

It is further provided that the at least one cover body include coolingfins. That “the at least one cover body include cooling fins” is to beunderstood to mean in particular that at least one body surface of thecover body has elevations, with the aid of which a surface area isenlarged compared with a flat surface area in order to achieve a higherheat emission and thus higher cooling of the cover body. A great heatemission of the cover body in particular may be achieved and greatheating of the cover body through waste heat may be avoided.

Furthermore it is provided that the battery charging device include atleast one fan which is provided to generate an airflow for cooling theelectronics housing. A “fan” is to be understood to mean in particular aunit including at least one ventilator which generates an airflow. That“at least one airflow for cooling the electronics housing” is to beunderstood to mean in particular that the airflow is directed at theelectronics housing. Advantageously, the airflow is directed at thecover body. Alternatively, or in addition, the battery charging devicemay include a cooling unit having an alternative cooling method, forexample a water cooling system. In particular a technically simple,stable cooling may be achieved.

Furthermore it is provided that the at least one fan is situated betweenthe cover body and the battery receiving space. In particular, the atleast one fan is situated in another space, which is delimited at leastpartly by the battery housing and which is at least partly separatedfrom the battery receiving space by a wall element of the batteryhousing. Alternatively, the fan may be situated in the battery receivingspace. Alternatively, the fan may be situated in the electronicsreceiving space, as seen in the direction toward the electronicsreceiving space, in front of the power electronics. Alternatively, thefan may be situated in an area, which, as seen from the batteryreceiving space, is situated behind the power electronics unit, eitherin the electronics receiving space or in a separate space. If the fan issituated inside the electronics receiving space within the water-tightand dust-tight electronics housing, it circulates air within theelectronics housing in order to create a cooling effect. This may inparticular achieve an advantageous routing of airflow.

Furthermore it is provided that the battery charging device include atleast one airflow routing means, which guides air past a batteryinserted into the at least one battery receiving space. The airflowrouting means is preferably designed as a channel inside the batteryhousing; alternatively, an airflow routing means which is designed as apipe is also conceivable. This may in particular achieve an advantageousrouting of airflow.

Furthermore it is provided that the battery charging device include atleast one locking means, which is provided to lock a battery insertedinto a battery receiving space at least in one state of charge. A “stateof charge” is to be understood to mean in particular an operating modeof the battery charging device in which a battery is charged. A “lockingmeans” is to be understood to mean in particular a means which, at leastin one operating mode, is in a form-fit engagement with the battery andwhich prevents movement on the part of the battery out of the batteryreceiving unit with this form-fit engagement. In particular, the batterywhich is to be charged may be secured against falling out accidentally.

Furthermore it is provided that the battery charging device include atleast one battery interface, which has at least one bare contactelement, for electrically contacting a battery. A “battery interface” isto be understood to mean in particular a unit having at least onecontact area for a battery having at least one contact element, whichcontacts a corresponding contact element of the battery and establishesan electrically conductive connection to the corresponding contactelement of the battery, this connection being used to transferelectrical power to charge the battery. A “bare contact element” is tobe understood to mean in particular a contact element which is at leastsituated within a space essentially exposed and essentially free fromany protective covering and/or protective coating against ashort-circuit. “At least essentially free from any protective coveringand/or protective coating” is to be understood to mean in particularthat a maximum of sixteen square millimeters, advantageously a maximumof eight square millimeters, and preferably a maximum of four squaremillimeters of the surface of a contact element is covered by aprotective covering and/or a protective coating. In particular, a barecontact element differs from a contact element which protrudes from aplug and which is provided for insertion into a plug connection. Thismay in particular achieve a high energy transmission capacity.

It is further provided that the at least one battery interface hasopenings for water drainage. “Openings for water drainage” are to beunderstood to mean in particular openings in the contact area throughwhich water, which enters into the battery receiving space, may escape.Thus, in particular, a battery charging device with a high operatingsafety may be achieved.

Furthermore it is provided that the battery housing is at least partly,preferably entirely, made of a plastic material and that the electronicshousing is made at least partly, preferably entirely, of metal. “Made atleast partly of a material” is to be understood to mean in particularthat at least seventy percent, advantageously at least eighty percent,preferably at least ninety percent, and particularly preferably onehundred percent of a mass of a material is made of this material.“Plastic material” is to be understood to mean in particular a purematerial or a material mix of materials from the group of materials ofplastics, such as, for example, polyethylene or polypropylene. “Metal”is to be understood to mean in particular a pure metal or an alloy.Preferably, the electronics housing is made of aluminum. In particular,the properties of the battery housing and the electronics housing may beadapted specifically to different requirements.

Furthermore it is provided that the battery charging device include ahandle, which, on one side, is joined to the battery housing and, on theopposite side, is joined to the electronics housing. The handle ispreferably at least partly designed as an elastic component; inprinciple, however, the handle may be designed as a rigid component.

In addition, a system including a battery charging device according tothe present invention and an at least partly water-tight battery isprovided. “An at least partly water-tight battery” is to be understoodto mean in particular a battery which may be used after it has beenentirely submerged in water and afterwards dried on the surface, andwhich provides a power during usage which is at most five percent lessthan the power provided before the submersion. This may in particularachieve a battery charge with a high operating safety.

The battery charging device according to the present invention is,however, not delimited to the applications and specific embodimentdescribed above. Here, the battery charging device according to thepresent invention may in particular have a number of elements,components and units which deviates from the number given here tofulfill the functionality described here.

Further advantages result from the following description of the drawing.One exemplary embodiment of the present invention is illustrated in thedrawing. The drawing, description, and claims contain numerous featuresin combination.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an overall view of a battery charging device according tothe present invention.

FIG. 2 shows a diagram of the battery charging device according to thepresent invention with an exposed battery receiving space.

FIG. 3 shows another view of the battery charging device according tothe present invention with an exposed battery receiving space.

FIG. 4 shows a cross section in top view through the battery chargingdevice according to the present invention.

FIG. 5 shows a detail illustration of the power electronics unit of thebattery charging device according to the present invention.

FIG. 6 shows a cross-sectional view of the battery charging deviceaccording to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a battery charging device 10 including a battery housing12, which partly delimits a battery receiving space 14, a powerelectronics unit 16 (concealed in FIG. 1, see FIG. 4) and including anelectronics housing 20 which was formed separately from battery housing12. Power electronics unit 16 is provided to supply a charging voltagefor charging a battery. Electronics housing 20 accommodates powerelectronics unit 16 in a water-protected and dust-protected manner. Thebattery charging device has a cuboid shape with a length of twenty-sevencentimeters, battery housing 12 and electronics housing 20 beingarranged in series and having a maximum width of seventeen centimeters.On a bottom side of battery housing 12 and electronics housing 20, fourfeet 50 are situated in order to set up battery charging device 10 on afloor.

Electronics housing 20 fulfills safety requirements corresponding to aprotection class according to the so-called IP code according to DIN EN60529 of IP67, so that electronics housing 20 is dust-tight and protectscontents against temporary submersion. Electronics housing 20 delimitsan electronics receiving space 18 (see FIG. 4) into which powerelectronics unit 16 is introduced. Battery housing 12 is made of aplastic material and electronics housing 20 is made of metal.

Battery charging device 10 is intended for charging batteries forelectrical equipment, such as, for example, lawn mowers, hand-heldcircular saws, percussion drills or the like, with a charging voltage of36 V. Power electronics unit 16 includes a current transformer unit,which transforms the current from a power grid to the charging voltage,and includes electronic units for sensing a state of charge of a batteryinserted into battery receiving space 14. The current from the powergrid is supplied via a cable, which is passed through a water-tight,threaded screw-joint 56, which is formed by a so-called PG fitting, intoan interior space of battery charging device 10. The electronic unitsfor sensing a state of charge of the inserted battery are connected to adisplay element 60, which is situated next to an opening of batteryreceiving space 14. Display element 60 is designed as an optical displayelement 60 and has two LEDs, which display the state of charge of thebattery as well as the charging mode.

Battery charging device 10 is, in particular, intended to quickly chargethe batteries immediately after an operation in a heated state and forthis includes a cooling unit 30. Power electronics unit 16 of batterycharging device 10 is dimensioned in such a way that a full charging ofa battery is completed with a charge of four ampere hours within half anhour.

Alternatively, battery charging device 10 may be provided to carry outtwo different charging modes, one normal charging mode, in which thebattery is charged over several hours, and a rapid-charge mode, in whichthe battery is charged completely within a time period between twentyminutes and half an hour. In the rapid-charge mode, high power lossesand thus high waste heat occur in power electronics unit 16 due to theoccurring electrical loads, which are considerably higher than theelectrical loads occurring in the normal charging mode.

Battery charging device 10 includes a handle 48, which is joined on oneside to the battery housing 12, and, on the opposite side, is joined tothe electronics housing 20. Handle 48 is designed as a flexible handle48 made of a sheet metal with a rubber covering.

One electronics housing 20 includes a cover body 24 and a principal body22 (FIG. 2). Principal body 22 delimits from five sides an electronicsreceiving space 18 (FIG. 4), into which power electronics unit 16 isinserted. Electronics receiving space 18 is completely enclosed by coverbody 24 and principal body 22. Principal body 24 and principal body 22are joined to each other by screws 52. Principal body 22 forms an outerpart, which may be touched by a user, of battery charging device 10.Cover body 24 has cooling fins 26, which protrude over an imaginary flatbase surface and which enlarge a surface area of cover body 24. In thisway, a heat-dissipating surface area is also enlarged, compared to aflat embodiment.

Electronics housing 20 has a sealing unit 28, which partly thermallydecouples cover body 24 and principal body 22. Power elements of powerelectronics unit 16 are joined to two circuit boards 66. In anotherembodiment, the power elements of the power electronics unit 16 may alsobe joined to a single circuit board 66. A heat transporting element 36(FIG. 5) thermally joins cover body 24 with power electronics unit 16.Heat transporting element 36 is formed by a cooling body made ofaluminum. Press-on elements 68, which are formed by steel squares, pressthe power elements of power electronics unit 16 against heattransporting element 36 so that a high heat transfer is achieved. Screws52 fix heat transporting element 36 to cover body 24 so that there is adirect contact with cover body 24 (FIG. 6). Heat transporting element 36has a heat transporting capacity which is more than four times as largeas the heat transporting capacity of surrounding components. Screws 52have a lower heat transporting capacity than heat transporting element36 so that a majority of the heat is dissipated via heat transportingelement 36 to cover body 24. Due to sealing unit 28, which is designedas a rubber seal, the dissipated waste heat primarily occurs at coverbody 24, and principal body 22 heats only slightly compared to coverbody 24. In particular, the temperature difference during a state ofcharge between cover body 24 and principal body 22 is at least 10degrees Celsius. Heating of principal body 22 of electronics housing 20during a maximum power output of power electronics unit 16 is delimitedto 50 degrees Celsius due to sealing unit 28 and cooling of cover body24, so that principal body 22 of electronics housing 20 and thus outwardlying components of battery charging device 10 may be touched briefly bya user without risk of injury.

Cooling unit 30 of battery charging device 10 includes a fan 32, whichis provided to generate an airflow to cool electronics housing 20. Fan32 is situated between cover body 24 and battery receiving space 14 inone other space which is partly divided from battery housing 14 by awall element 62 of battery housing 12. Fan 32 cools electronics housing20 in one operating mode from outside, the airflow being directed ontocover body 24. Wall element 62 has slot-shaped through-openings 64,through which fan 32 sucks in air from an exterior space. Batterycharging device 10 has an airflow routing means 34, which guides airpast a battery inserted into the at least one battery receiving space14. Airflow routing means 34 is designed as a side channel, which isformed by a recessed subarea of battery housing 12. The airflow isguided onto cooling fins 26 of cover body 24 and dissipates the heatthere. By heating the air sucked in by fan 32, a higher air extractioncapacity is achieved.

In alternative embodiments of the present invention, the fan may besituated in battery receiving space 14, in electronics receiving space18 in front of power electronics unit 16, as seen toward batteryreceiving space 14, in an area which is behind power electronics unit16, as seen from battery receiving space 14, either inside electronicsreceiving space 18 or in a space which is separate from electronicsreceiving space 18.

Battery charging device 10 includes a locking means 38 (FIG. 3), whichis provided to lock a battery inserted into a battery receiving space 14in at least one state of charge. Locking means 38 is situated in batteryreceiving space 14 and establishes a force-fitting contact with abattery inserted in battery receiving space 14 so that the battery isfixed in a position. In particular, battery charging device 10 may beaccommodated and moved without any risk of the battery falling out.Locking means 38 is mechanically connected to an actuator 58, which issituated at battery housing 12 next to the opening of battery receivingspace 14. By pressing down actuator 58, locking means 38 is pulled intobattery housing 12 so that the battery may be removed.

Battery charging device 10 includes a battery interface 40 situatedinside battery receiving space 14 (see FIG. 4) for electricallycontacting a battery. Three bare contact elements 44 are situated in acontact area 42 of battery interface 40. A charging current flows viacontact elements 44 to a battery contacting contact elements 44. Batteryinterface 40 has a plastic base body, which is accommodated in a recessof battery housing 12, which is provided for this purpose, where it isfixed with screws 52. The battery interface 40 is connected via a powerline element 54 to power electronics unit 16, and is supplied by powerelectronics unit 16 with power having the charging voltage. One branchof power line element 54 supplies fan 32 with power (FIG. 2). Batteryinterface 40 has openings for water drainage 46, which are introduced inthe plastic base body and through which water is drained. The waterflows through the openings for water drainage 46 into a cavity ofbattery housing 12, where it is drained through slots in a bottom ofbattery housing 12. Battery charging device 10 may thus also be usedsafely when water enters battery receiving space 14, for example rainwater, to charge an at least partly water-tight battery. Sinceelectronics housing 20 is water-tight, power electronics unit 16 isprotected against water penetrating battery receiving space 14. Fan 32is also protected against water damage. Battery interface 40 has abattery insertion direction which is directed toward the one fan 32.

What is claimed is:
 1. A battery charging device, comprising: a batteryhousing which delimits a battery receiving space at least in part; apower electronics unit supplying a charging voltage; and an electronicshousing which is (i) separate from the battery housing and (ii)accommodates the power electronics unit in at least one ofwater-protected manner and dust-protected manner.
 2. The batterycharging device as recited in claim 1, wherein the electronics housingincludes at least one cover body and one principal body.
 3. The batterycharging device as recited in claim 2, wherein the electronics housingincludes at least one sealing unit which at least partly thermallydecouples the at least one cover body and the principal body.
 4. Thebattery charging device as recited in claim 2, further comprising: atleast one heat transporting element which thermally connects the atleast one cover body to the power electronics unit.
 5. The batterycharging device as recited in claim 2, wherein the at least one coverbody has cooling fins.
 6. The battery charging device as recited inclaim 2, further comprising: at least one fan generating an airflow tocool the electronics housing.
 7. The battery charging device as recitedin claim 6, wherein the at least one fan is situated between the atleast one cover body and the battery receiving space.
 8. The batterycharging device as recited in claim 6, further comprising: at least oneairflow routing element which guides air past a battery inserted intothe battery receiving space.
 9. The battery charging device as recitedin claim 8, further comprising: at least one locking element which locksthe battery inserted into the battery receiving space in at least onestate of charge.
 10. The battery charging device as recited in claim 8,further comprising: at least one battery interface electricallycontacting a battery which has at least one bare contact element. 11.The battery charging device as recited in claim 10, wherein the at leastone battery interface has openings for water drainage.
 12. The batterycharging device as recited in claim 10, wherein the at least one batteryinterface has a battery insertion direction, which is directed towardthe at least one fan.
 13. The battery charging device as recited inclaim 8, wherein the battery housing is made at least partly of aplastic material and the electronics housing is at least partly madefrom metal.
 14. The battery charging device as recited in claim 8,further comprising: a handle which is joined on one side to the batteryhousing and joined on the opposite side to the electronics housing.